U.S. patent application number 10/990574 was filed with the patent office on 2006-05-18 for lift wheelchair.
Invention is credited to Thomas G. Kelso.
Application Number | 20060103115 10/990574 |
Document ID | / |
Family ID | 36385465 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060103115 |
Kind Code |
A1 |
Kelso; Thomas G. |
May 18, 2006 |
LIFT WHEELCHAIR
Abstract
A wheelchair that enables its occupant to lower and raise their
self to and from the surface on which the wheelchair is resting so
that the occupant may enter the wheelchair from the surface without
the aid of another person, the wheelchair a lower support frame, a
seat frame assembly vertically movable relative to the lower
support frame, a lifting assembly connected to the lower support
frame and to the seat frame assembly, a planar ramp rotatably
connected to the seat frame, the planar ramp rotating to form an
inclined plane relative to the plane of the seat frame, the planar
ramp rotating to a vertical position relative to the horizontal
seat beneath the horizontal seat when the seat frame assembly is at
its highest vertical position, and a footrest rotatably, the
footrest rotating to a horizontal position when the seat frame
assembly is at its highest vertical position, the footrest rotating
downward beneath the ramp when the seat frame assembly is at its
lowest vertical position.
Inventors: |
Kelso; Thomas G.; (Baton
Rouge, LA) |
Correspondence
Address: |
PATENT DEPARTMENT;TAYLOR, PORTER, BROOKS & PHILLIPS, L.L.P
P.O. BOX 2471
BATON ROUGE
LA
70821-2471
US
|
Family ID: |
36385465 |
Appl. No.: |
10/990574 |
Filed: |
November 17, 2004 |
Current U.S.
Class: |
280/649 ;
280/250.1 |
Current CPC
Class: |
A61G 5/1059 20130101;
A61G 5/10 20130101; A61G 7/1038 20130101; A61G 7/1011 20130101;
A61G 5/1054 20161101; Y10S 297/04 20130101 |
Class at
Publication: |
280/649 ;
280/250.1 |
International
Class: |
B62M 1/14 20060101
B62M001/14 |
Claims
1. A wheelchair that enables an occupant to lower and raise their
self to and from the surface on which the wheelchair is resting so
that the occupant may enter the wheelchair from said surface
without the aid of another person, the wheelchair comprising: a. a
lower support frame having two drive wheels and two casters
connected thereto, b. a seat frame assembly vertically movable
between said two drive wheels, said seat frame assembly having a
horizontal seat connected thereto, c. a lifting assembly connected
to said lower support frame and to said seat frame assembly for
vertically moving said seat frame assembly upward and downward
between said two drive wheels, d. a planar ramp rotatably connected
to said seat frame, said planar ramp rotating to form an inclined
plane relative to the plane of said horizontal seat to provide an
inclined planar surface for said occupant to slide upon when said
occupant is exiting or entering said horizontal seat when said seat
frame is at the lowest vertical position, said planar ramp rotating
to a vertical position relative to said horizontal seat beneath
said horizontal seat when said seat frame assembly is at the
highest vertical position, and e. a footrest rotatably connected to
said lower support frame for supporting the feet of said occupant
when said seat frame assembly is at the highest vertical position,
said footrest rotating to a horizontal position when said seat
frame assembly is at the highest vertical position, said footrest
rotating downward beneath said ramp when said seat frame assembly
is at the lowest vertical position.
2. The wheelchair of claim 1 wherein said lifting assembly has an
electric motor connected thereto for supplying lifting force to
said lifting assembly.
3. The wheelchair of claim 1 wherein said wheelchair has a battery
for supplying electrical energy to said electric motor.
4. The wheelchair of claim 1 wherein said electric motor has a
switch connected thereto for operating said electric motor to raise
or lower said seat frame assembly.
5. A wheelchair that enables an occupant to lower and raise their
self to and from the surface on which said wheelchair is resting so
that the occupant may enter the wheelchair from said surface
without the aid of another person, the wheelchair comprising: a. a
rectangular support frame having a front end, a rear end, and two
opposite sides, said rectangular support frame having a drive wheel
connected to each of said two opposite sides of said support frame,
said rectangular support frame having two casters connected
thereto, b. a rectangular seat frame having a front end, a rear
end, and two opposite sides, said rectangular seat frame being
located above said rectangular support frame, said rectangular seat
frame being vertically movable between said two drive wheels, said
rectangular seat frame having a horizontal seat connected thereto,
c. a lifting assembly connected to said rectangular support frame
and to said rectangular seat frame for vertically moving said seat
frame assembly upward and downward between said two drive wheels,
d. a planar ramp rotatably connected to said front end of seat
frame, at least one pushrod connected to said planar ramp and to
said support frame for rotating said planar ramp to an inclined
plane relative to said horizontal seat when said seat frame is at
the lowest vertical position to provide an inclined planar surface
for said occupant to slide upon when said occupant is exiting or
entering said horizontal seat, said planar ramp being rotated by
said pushrod to a vertical position relative to said horizontal
seat when said horizontal seat is at the highest vertical position,
and f. a footrest rotatably connected to said front end of said
rectangular support frame for supporting the feet of said occupant
when said seat frame assembly is at the highest vertical position,
at least one pushrod connected to said footrest and to said
rectangular support frame for rotating said footrest to a
horizontal position when said rectangular seat frame is at the
highest vertical position, said footrest being rotated by said
pushrod downward at an inclined angle to said rectangular support
frame beneath said planar ramp when said seat frame assembly is at
the lowest vertical position.
6. The wheelchair of claim 5 wherein said lifting assembly has an
electric motor connected thereto for supplying lifting force to
said lifting assembly.
7. The wheelchair of claim 5 wherein said wheelchair has a battery
for supplying electrical energy to said electric motor.
8. The wheelchair of claim 5 wherein said electric motor has a
switch connected thereto for operating said electric motor to raise
or lower said seat frame assembly.
9. The wheelchair of claim 5 wherein said lifting assembly
comprises a scissor-lift mechanism having a. a first pair of two
elongated cross-members rotatably connected together by a pin, and
b. a second pair of two elongated cross-members rotatably connected
together by a pin.
10. The wheelchair of claim 9 wherein each pair of said two
elongated cross-members lie in spaced-apart parallel vertical
planes between said two drive wheels, and at least two brace
members are connected perpendicularly between each cross-member of
each pair of said two elongated cross-members.
11. The wheelchair of claim 10 wherein each of said cross-members
has an upper end and a lower end, said upper end of each of said
cross-members being connected to said rectangular seat frame and
said lower end of each of said cross-members being connected to
said rectangular support frame.
12. The wheelchair of claim 11 wherein said upper end of one of
each pair of said cross-members is rotatably pinned to said seat
frame assembly, and the lower end of one of each pair of said
cross-members is rotatably pinned to said support frame.
13. The wheelchair of claim 12 wherein said upper end of one of
each pair of said cross-members has a bearing connected thereto
which is slidably received in an elongated slot in said rectangular
seat frame, and the lower end of one of each pair of said
cross-members has a bearing connected thereto which is slidably
received in an elongated slot in said rectangular support
frame.
14. A wheelchair that enables an occupant to lower and raise their
self to and from the surface on which the wheelchair is resting so
that the occupant may enter the wheelchair from said surface
without the aid of another person, the wheelchair comprising: a. a
lower support frame means having two drive wheels and two casters
connected thereto, b. a seat frame assembly means vertically
movable between said two drive wheels, said seat frame assembly
having a horizontal seat connected thereto, c. a lifting assembly
means connected to said lower support frame and to said seat frame
assembly for vertically moving said seat frame assembly upward and
downward between said two drive wheels, d. a planar ramp means
rotatably connected to said seat frame, said planar ramp rotating
to form an inclined plane relative to the plane of said horizontal
seat to provide an inclined planar surface for said occupant to
slide upon when said occupant is exiting or entering said
horizontal seat when said seat frame is at the lowest vertical
position, said planar ramp rotating to a vertical position relative
to said horizontal seat beneath said horizontal seat when said seat
frame assembly is at the highest vertical position, and e. a
footrest means rotatably connected to said lower support frame for
supporting the feet of said occupant when said seat frame assembly
is at the highest vertical position, said footrest rotating to a
horizontal position when said seat frame assembly is at the highest
vertical position, said footrest rotating downward beneath said
ramp when said seat frame assembly is at the lowest vertical
position.
15. The wheelchair of claim 14 wherein said lifting assembly has an
electric motor connected thereto for supplying lifting force to
said lifting assembly.
16. The wheelchair of claim 14 wherein said wheelchair has a
battery for supplying electrical energy to said electric motor.
17. The wheelchair of claim 14 wherein said electric motor has a
switch connected thereto for operating said electric motor to raise
or lower said seat frame assembly.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to wheelchairs. In particular,
the present invention is related to wheelchairs which provide
access to the wheelchair from ground level.
[0003] 2. Description of the Related Art
[0004] Wheelchairs are well known in the art and have been in
existence for many years. Wheelchair design has undergone extensive
modification and refinement, yet the basic design of most
wheelchairs has remained relatively consistent. Typical wheelchairs
of the past had two large drive wheels connected by an elongated
rigid axle supporting a frame or seat on which an individual may be
seated. Later versions of the wheelchair eliminated the elongated
axle connecting the large drive wheels, but the support frame or
other structural members prevented the seat from being moved below
a pre-established height.
[0005] Some physically disabled persons utilizing a wheelchair,
such as paraplegics having normal upper body strength, may engage
in physical exercises conducted while sitting or lying supine on
the floor or ground. Such a person may also desire to sit on the
ground for gardening or for playing with their young children or
grandchildren. Such persons commonly require assistance to be
lowered to the floor or ground from a conventional wheelchair seat
to perform such exercises or tasks.
[0006] Exemplary of the related art are the following: U.S. Pat.
Nos. 3,123,400; 4,415,202; 5,601,302; and 6,467,785; U.S. Patent
Application Publication Numbers US 2003/0218310 A1 and US
2004/0075237 A1; European Patent Publication EP 1 133 968 A3; Japan
Publication Number 2001299822 A and Japan Publication Number
2002153514 A.
BRIEF SUMMARY OF THE INVENTION
[0007] In accordance with the present invention there is provided a
wheelchair that enables its occupant to lower and raise their self
to and from the surface on which the wheelchair is resting so that
the occupant may enter the wheelchair from the surface without the
aid of another person, the wheelchair a lower support frame, a seat
frame assembly vertically movable relative to the lower support
frame, a lifting assembly connected to the lower support frame and
to the seat frame assembly, a planar ramp rotatably connected to
the seat frame, the planar ramp rotating to form an inclined plane
relative to the plane of the seat frame, the planar ramp rotating
to a vertical position relative to the horizontal seat beneath the
horizontal seat when the seat frame assembly is at its highest
vertical position, and a footrest rotatably, the footrest rotating
to a horizontal position when the seat frame assembly is at its
highest vertical position, the footrest rotating downward beneath
the ramp when the seat frame assembly is at its lowest vertical
position.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0008] FIG. 1 is a side elevational view of the lift wheelchair of
the invention in the normal elevated position having an occupant
shown in phantom lines sitting therein;
[0009] FIG. 2 is a side elevational view of the lift wheelchair of
the invention in the lowered position having an occupant shown in
phantom lines sitting therein;
[0010] FIG. 3 is a partly cut-away, partly schematic side
elevational view of the lift wheelchair of the invention in the
normal elevated position of FIG. 1 showing the scissor lift
components in greater detail with some of the tubular support frame
components removed;
[0011] FIG. 4 is a partly cut-away, partly schematic side
elevational view of the lift wheelchair of the invention in an
intermediate lowered position between the position of FIG. 1 and of
FIG. 2 showing the scissor lift components in greater detail with
some of the tubular support frame components removed;
[0012] FIG. 5 is a partly cut away, partly schematic side
elevational view of the lift wheelchair of the invention in the
lowered position of FIG. 2 showing the scissor lift components in
greater detail with some of the tubular support frame components
removed;
[0013] FIG. 6 is a partly cut-away, partly schematic side
elevational view of the lift wheelchair of the invention in the
lowered position of FIGS. 2 and 5 showing the scissor lift
components in greater detail with some of the tubular support frame
components removed and an occupant shown in phantom lines utilizing
an access frame to mount or exit the lift wheelchair of the
invention;
[0014] FIG. 7 is an exploded perspective view of the lift
wheelchair of the invention with one drive wheel removed, the
casters removed, and one drive wheel partly-cut away;
[0015] FIG. 8 is a partly cut-away, detailed perspective view of
the hand brake of the invention;
[0016] FIG. 9 is an enlarged perspective view of the access frame
of the invention shown in FIG. 6 utilized to mount or exit the lift
wheelchair of the invention from the ground or floor; and
[0017] FIG. 10 is an enlarged exploded perspective view of the
pushrods and slot plates of the lift wheelchair of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to the drawings, the lift wheelchair of the
invention enables a disabled person such as a paraplegic having
normal upper body strength to lower the seat of the lift wheelchair
of the invention from the position shown in FIG. 1 to the surface G
upon which the wheelchair is resting to the lowered position shown
in FIG. 2 to enable the disabled person to exit from the lift
wheelchair as shown in FIG. 6 to the surface G without the aid of
another person.
[0019] The lift wheelchair of the invention is supported by two
conventional wheelchair drive wheels generally indicated by the
numerals 10-10 and two conventional casters generally indicated by
the numerals 11-11 mounted near the front of the lift wheelchair.
Drive wheels 10-10 are grasped by the hands of the occupant of the
lift wheelchair and rotated to propel the lift wheelchair in the
desired direction as known in the wheelchair art.
[0020] Drive wheels 10-10 and casters 11-11 are connected to a
lower tubular support frame generally indicated by the numeral 12
and shown in perspective in FIG. 7. Lower support frame 12 has two
wheel arches generally indicated by the numerals 14-14 for
rotatably receiving drive wheels 10-10. Preferably each of the
wheel arches 14-14 are constructed from one or more sections of
tubing having a circular cross-section.
[0021] Each of the two wheel arches 14-14 is connected at their
lower ends to one of two parallel square tubing sections 16-16.
Square tubing sections 16-16 extend the length of lower support
frame 12. The inside face of each of square tubing sections 16-16
has an elongated slot 16a machined therein for receiving roller
bearings 18-18. Roller bearings 18-18 are rotatably connected to
the lower end of the cross-members 19-19 of the scissor-lift
assembly generally indicated by the numeral 20. Cross-members 19-19
have a plurality of brace members 19a, 19b, 19c and 19d extending
perpendicularly therebetween. Each slot 16a is of sufficient length
to allow bearing 18 to roll through the full range of motion of
scissor-lift assembly 20 as scissor-lift assembly 20 is lowered
from the highest position shown in FIGS. 1 and 3 to the lowest
position shown in FIGS. 2, 5, and 6.
[0022] Each square tubing section 16-16 has a cylindrical hole 16b
shown in FIG. 7 therein for rotating receipt of two pivot bushings
22-22 shown at the lower end of the cross-members 24-24 of
scissor-lift assembly 20. Cross-members 24-24 have a plurality of
brace members 24a, 24b, 24c and 24d extending perpendicularly
therebetween. Preferably pivot bushings 22-22 are fastened to
square tubing sections 16-16. Pivot bushings 22-22 serve as the
bearing surface through which pivot pins 22a-22a are inserted and
then tightened into each end of brace member 24d. Brace member 24d
serves as the non-rolling forward end of cross-member 24-24 of the
scissor-lift assembly 20. Each pair of cross-members 19 and 24 is
rotatably connected by pin 26. Preferably, pin 26 is located at a
point approximately 40% of the distance between the brace members
at each end of 19-19 and 24-24 and approximately one inch below the
centerline formed by the brace members at each end of 19-19 and
24-24.
[0023] Each square tubing section 16-16 is joined parallel to the
opposite square tubing section 16 with slots 16a facing inward by
one or more square tubing cross-members 28 shown in FIG. 7. Square
tubing cross-members 28 are located toward the front ends of
cross-members 24, forward of, and in close proximity to pivot
bushings 22 to provide adequate clearance for the movement of
scissor-lift assembly 20 and to provide maximum structural strength
and rigidity for the two parallel square tubing sections 16-16
supporting scissor-lift assembly 20.
[0024] Wheel arches 14-14 are attached to each of the square tubing
sections 16-16 at a location that provides the optimal center of
gravity to allow the lift wheelchair occupant the greatest level of
stability while still enabling the lift wheelchair occupant to
perform "wheelies" for obstacle clearance. By "wheelies" is meant
the procedure of forcing casters 11-11 up from the surface G upon
which the lift wheelchair is traveling by the occupant turning the
drive wheels forward with sufficient force and torque to lift
casters 11 over obstacles confronted by the lift wheelchair of the
invention. The location of wheel arches 14-14 on lower support
frame 12 enables the occupant of the lift wheelchair to perform a
"wheelie" without having the lower support frame come into contact
with the surface G on which the lift wheelchair is traveling.
[0025] Wheel arches 14-14 may be made as separate units (two
separate arches) or preferably as a single unit (both arches formed
on one continuous length of tubing) and integrated into the lower
support frame 12 as shown in the drawings and in particular in FIG.
7. As shown in the drawings, the wheel arches 14-14 are formed from
a single piece of tubing having a circular cross-section. Wheel
arches 14-14 have an elongated section 14a connected
perpendicularly to the rear ends of each of the square tubing
sections 16-16 to function as the rear supporting member of the two
parallel square tubing sections 16-16. Wheel arches 14-14 are
preferably formed by bending a length of tubing in a sequential
manner in a combination of angles and directions to produce the
wheel arches 14-14 and integral elongated section 14a. Wheel arches
14-14 are formed so that each wheel arch 14 is perpendicular to
elongated section 14a and each wheel arch 14 is parallel to the
other wheel arch 14.
[0026] Vertical adjusting brackets 29-29 are connected to the front
and rear inside surfaces of both wheel arches 14-14. Each adjusting
bracket 29 is a flat plate having a plurality of bolt receiving
holes 29a therein for receiving bolts to connect axle blocks 30-30
to adjusting brackets 29-29 at various desired heights to enable
vertical adjustment of axle blocks 30-30. Each axle block has bolt
receiving holes therein for receiving bolts 31 to connect axle
block 30 to brackets 29.
[0027] Axle blocks 30-30 are manufactured from a material of
sufficient thickness so that the finished block will not flex or
distort under normal circumstances from the weight of the lift
wheelchair and its occupant. Each axle block 30 is of adequate
height and length to allow for vertical adjustment in the adjusting
brackets 29. Each axle block 30 has a horizontal slot 30a therein
for receipt of axle support bushing 10b. Horizontal adjustment for
drive wheels 10 is achieved by moving axle support bushings 10b to
desired position in slot 30a. The axle support bushings 10b receive
axles 10a of drive wheels 10.
[0028] Two U-shaped wheel arch support braces 32 and 34 are
connected to the rear vertical sections of the wheel arches 14-14
and extend therebetween to provide vertical alignment of the wheel
arches 14-14. The width of the wheel arch support braces 32 and 34
matches the width or distance that the wheel arches 14-14 is spaced
apart. The depth of wheel arch support braces 32 and 34 is selected
to be sufficient for the seat frame assembly generally indicated by
the numeral 36 and the battery box generally indicated by the
numeral 37 to move inside of wheel arch support braces 32 and 34 as
the scissor-lift assembly 20 moves the seat frame assembly 36
upward and downward.
[0029] A U-shaped front wheel arch support brace generally
indicated by the numeral 38 is connected to the front vertical
sections of the wheel arches 14-14 and extend therebetween to
provide vertical alignment of the wheel arches 14-14. Front wheel
arch support brace 38 has horizontal portions 38a-38a each of which
are parallel to one of the square tubing sections 16-16. Front
caster assemblies generally indicated by the numeral 40-40 are
attached to horizontal portions 38a-38a as shown in FIG. 1, and the
handbrake assemblies generally indicated by the numerals 42-42 is
also attached to horizontal portions 38a-38a. Caster assemblies
40-40 are conventional wheel chair caster assemblies well known in
the art, and handbrake assemblies 42-42 are conventional wheelchair
brake assemblies well known in the art.
[0030] Front wheel arch support brace 38 has two downward sloping
portions 38b-38b connected perpendicularly by a straight horizontal
cross-member 38c which is connected to the front ends of each of
the square tubing sections 16-16. Preferably, front wheel arch
support 38 is formed by bending a length of tubing having a
circular cross-section in a sequential manner in a combination of
angles and directions to provide support and structural strength
for wheel arches 14-14 and to provide cross-member 38c connected to
the front ends of each of the square tubing sections 16-16.
[0031] Connected to the top front end of square tubing sections
16-16 is stationary footrest 43. Stationary footrest 43 has a
concave front lip 43a which fits over the top of cross-member 38c.
Stationary footrest 43 is made from a material of sufficient
thickness and strength to provide a semi-rigid surface capable of
supporting the weight of the occupant without excessive bending or
flexing. The material from which stationary footrest 43 is made is
such that it can be machined or molded using standard techniques
known in the art. A variety of polymeric materials commonly
referred to as plastics may be used and are preferred.
[0032] A rotatable footrest 44 is rotatably connected to
cross-member 38c by a hinge 38d. Rotatable footrest 44 provides
additional length to stationary footrest 43 for resting the feet of
the occupant when the lift wheelchair of the invention is in the
fully raised position of FIGS. 1 and 3. Preferably, rotatable
footrest 44 is made from aluminum about one-eighth inch thick. The
rotatable footrest cover 44D is made from the same material from
which stationary footrest 43 is made. Two pushrods 45-45 are each
rotatably connected at their front ends to brackets 44a-44a by pin
44b on the bottom side of movable foot rest 44.
[0033] Seat frame assembly 36 includes two parallel square tubing
sections 46-46. Square tubing sections 46-46 are connected at their
ends to the rectangular seat frame generally indicated by the
numeral 48 preferably made from metal tubing having a circular
cross-section. The inside face of each of square tubing sections
46-46 has an elongated slot 46a machined therein for receiving
roller bearings 18a-18a. Roller bearings 18a-18a are rotatably
connected to the upper end of the cross-members 24-24 of the
scissor-lift assembly generally indicated by the numeral 20. Each
slot 46a is of sufficient length to allow bearing 18a to roll
through the full range of motion of scissor-lift assembly 20 as
scissor-lift assembly 20 is raised to the highest position shown in
FIGS. 1 and 3 to the lowest position shown in FIGS. 2, 5, and
6.
[0034] Each square tubing section 46-46 has a cylindrical hole 46b
therein for rotating receipt of two pivot bushings 23-23. These
pivot bushings serve as the bearing surface through which pivot
pins 45a are inserted and then tightened into the ends of brace
member 19a. Pivot bushings 23-23 serve as the pivot locations for
the non-rolling upper forward ends of cross-members 19-19 of the
scissor-lift assembly 20.
[0035] Each square tubing section 46 is joined to the opposite
square tubing section 46 with slots 46a facing inward by one or
more square tubing cross-members 50. Square tubing cross-member 50
is located near the center of square tubing sections 46 to provide
maximum structural strength and rigidity for the two parallel
square tubing sections 46-46 and seat frame 48 supporting the seat
assembly generally indicated by the numeral 52.
[0036] Extending upward from seat frame 48 is the adjustable seat
back assembly generally indicated by the numeral 54. Seat back
assembly 54 includes two vertical lengths of tubing 56-56 connected
by U-shaped cross-member 58. The two vertical lengths of tubing
56-56 are connected at their lower ends to adjustable seat brackets
generally indicated by the numerals 58-58 which are connected to
seat frame 48. A lever assembly 60 is connected to the lower end of
each of the two vertical lengths of tubing 56-56 to lock each of
the vertical lengths of tubing 56-56 at a predetermined angle to
adjustable seat brackets 58-58.
[0037] Preferably the two lengths of tubing 56-56 are encapsulated
with a fabric seat back cover 57a held by straps 57b. Molded seat
48a is connected to seat frame 48.
[0038] A rotating ramp 62 is connected near the front end of seat
frame 48 by pins 64a to two ramp support brackets 64-64. One ramp
support bracket 64 is rigidly connected to the bottom of each of
the two parallel square tubing sections 46-46.
[0039] One of two pushrods 66-66 is rotatably connected at its
front end by pin 62a to one of the two brackets 62b-62b shown in
phantom lines in FIG. 10 on the bottom side of rotating ramp 62. As
shown in FIG. 10, each of the pushrods 66-66 is rotatably connected
at its rear end to one of the push rod brackets 68-68 by shoulder
bolt 68a. Shoulder bolt 68a has a cylindrical center portion 69
which has a smooth outer surface about which pushrods 66-66 rotate.
Pushrod brackets 68-68 are rigidly connected to the top of each of
the square tubing sections 16-16 by screws 68b-68b. Pushrods 66-66
have two parallel slot plates 70-70 connected thereto by bolt 68a
and screw 72. Screw 72 causes slot plates 70-70 to rotate about
center portion 69 of shoulder bolt 68a as pushrods 66-66 rotate
about shoulder bolt 68a.
[0040] Each of the slot plates 70 have a curved elongated slot 70a
located on the lower end of slot plate 70 beneath shoulder bolt
68a. A pushrod pin 72 extends through the slots 70a of a pair of
slot plates 70-70 on each side of square tubing section 16 and
through the bracket 45a on the rear end of pushrod 45 to rotatably
connect pushrod 45 to slots 70a.
[0041] An electric motor assembly generally indicated by the
numeral 74 is connected to brace members 19b and 24b. Motor
assembly 74 includes linear electric motor 76 rotatably connected
by bracket 78 to brace member 19b. Extending from electric motor 76
is an externally threaded rotating drive screw 80 which is received
in internally threaded clutch 82. Internally threaded clutch 82 is
rotatably connected to bracket 84 which is rigidly connected to
brace member 24b.
[0042] Electrical energy is supplied to electric motor 76 by
battery 86. Battery 86 is held in battery box 37 having a lid 90
for covering the top of battery 86. Battery box 37 has a lower
curved lip 88a which is connected to the rear end of rectangular
seat frame 48. Lower curved lip 88b fits over and rests on square
tubing 46-46. A hand held switch 92 is connected by electrical
wires 92a to electrical wires 86a and 86b of battery 86 and to
electric motor 76 to selectively energize electric motor 76. Hand
held switch has one switch button 94 for energizing electric motor
76 to rotate drive screw 80 in one direction to lower seat frame 48
and another button 96 for energizing electric motor 76 to rotate
drive screw 80 in the opposite direction to raise seat frame
48.
[0043] To lower the occupant and seat frame 48 from the position
shown in FIGS. 1 and 3 to the position shown in FIGS. 2, 5, and 6,
button 94 is depressed to energize electric motor 76 and rotate
drive screw 80 in the direction indicated by the arrow 98 in FIGS.
3 and 4. Clutch 82 and bracket 84 is forced away from bracket 78
causing cross-members 19-19 to rotate in the direction indicated by
the arrow 102 in FIG. 4 and causing cross-members 24-24 to rotate
in the direction indicated by the arrow 100 in FIG. 4. As
cross-members 24-24 rotate in the direction indicated by the arrow
100, bearings 18a-18a move toward the rear end of slots 46a-46a. As
cross-members 19-19 rotate in the direction indicated by the arrow
102, bearings 18-18 move toward the rear end of slots 16a-16a. As
seat frame 48 descends, pushrods 66-66 force ramp 62 to rotate
upward in the direction indicated by the arrow 104 in FIG. 4, and
footrest 44 rotates downward in the direction indicated by the
arrow 106 in FIG. 4 as slot plate 70 and slot 70a rotate clockwise
about shoulder bolt 68a, thereby enabling pin 72 in pushrod 45 to
be forced by the weight of footrest 44 toward the rear end of slot
70a. When seat frame 48 reaches the position shown in FIG. 5, pin
72 is forced against the front end of slot 70a, thereby retracting
pushrod 45 to its rear-most position to rotate footrest 44 to the
position shown in FIGS. 5 and 6.
[0044] As shown in FIGS. 6 and 9, an access frame generally
indicated by the numeral 110 may be utilized to assist the occupant
in entering and exiting the lift wheelchair of the invention when
the seat frame 48 is in the lowest position. Access frame 110
includes two U-shaped parallel hand rail sections generally
indicated by the numeral 112 having a horizontal hand rail 112a
with two vertical support legs 112b connected to each end thereof.
Preferably, a horizontal brace 112c is connected between opposite
vertical support legs 112b at the approximate midpoint thereof.
Each of the two U-shaped hand rail sections 112 are connected at
ground level G of access frame 110 by cross-member 112d which is
connected perpendicularly to opposite vertical legs 112b and
perpendicularly to hand rail sections 112. To prevent the front
legs of the access frame from lifting up once body weight is
applied to the rearward portion of the access frame hand rails a
U-shaped wheel blocking section 112e is connected perpendicularly
to cross-member 112d parallel to the ground G extending in a
direction opposite to the direction in which hand rails 112a
extend.
[0045] As best shown in FIGS. 1 and 6, to utilize the access frame
110 to dismount or exit the lift wheelchair of the invention, the
occupant of the lift wheelchair of the invention rolls drive wheels
10-10 forward to drive casters 11-11 into access frame 110 until
the casters 11-11 lie between the two U-shaped hand rail sections
112 past cross-member 112d, and U-shaped wheel blocking section
112e lies between drive wheels 10-10 and casters 111-1. The
occupant then lowers seat frame 48 from the position shown in FIG.
1 to the position shown in FIG. 6 utilizing hand held switch 92.
The handbrakes 42 are then actuated by the occupant to lock drive
wheels 10-10. Next, the occupant grasps opposite hand rails 112a
with each of the occupant's hands, and the occupant pulls forward
in the direction indicated by the large arrow 114 to exit or
dismount from the lift wheelchair of the invention. Ramp 44
provides an inclined plane for assisting the occupant in exiting,
or entering, the lift wheelchair of the invention. The front edge
44c of rotatable footrest 44 rotates downward to the ground level G
to provide clearance for the front edge 62c of ramp 62 to rotate to
the ground level G. Cross-member 112d contacts the drive wheels
10-10 or casters 11-11 if the access frame 110 slides forward or
backward during the exit or dismount of the occupant from the lift
wheelchair of the invention.
[0046] When an individual lying on surface G wishes to enter or
mount the lift wheelchair of the invention, the procedure of the
preceding paragraph is reversed.
[0047] Although the preferred embodiments of the invention have
been described in detail above, it should be understood that the
invention is in no sense limited thereby, and its scope is to be
determined by that of the following claims:
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